Diffuse Low Grade Glioma, MAPK Pathway-Altered

**Semantic type:** Neoplastic Process

**Definition:** A rare, low-grade diffuse glioma with morphological features of astrocytoma or oligodendroglioma, generally affecting children. It is characterized by a gene alteration that results in a MAPK pathway abnormality. The genetic abnormalities are typically a BRAF p.V600E substitution mutation, mutations or fusions involving the FGFR1 gene and internal tandem duplication (ITD) of the sequences of FGFR1 gene encoding the tyrosine kinase domain (TKD). The tumor is IDH-wildtype and does not have a homozygous deletion of CDKN2A gene.

**Synonyms:** - Diffuse Low-Grade Glioma, MAPK Pathway-Altered